hello, I have attached 2 pics - one of my yucca when it was first planted, nice round head, good proportions. then one of it now...big trunk, small head and leaves.  It is next to 2 small olive trees, it is not in the shade. I was told not to water it so I don't, unless its very hot in summer.  How do I get the leaves nice and long again?

Leaves once damaged never improve. Just wait for the summer heat.

Important, history -related  questions:

How long has it been in the ground?

What time of year was it planted?

Grown in a pot, or field dug ..IE: uprooted from a place where they are grown in the ground?

All of this is important in determining what to do next.. 


While it is true you don't want to soak it ....frequently..  a big plant like that has to receive  some   water after being planted,  esp if not planted in the fall / time of year when it might receive some rainfall provided irrigation after installation. 

If it had been grown in a greenhouse, it may shrink a bit as it adjusts to life outside in the real world ..as a pose to the " near perfect " conditions inside a G.H.

If you can access it, how does the crown look / feel?  ..Tight? ..or sorta wobbly?  Wobbly could mean trouble ( rot issue or something else ) 

Tight/ not seeing any brown where the leaves emerge from the growth point(s) in the crown??  it should pull out of it's current funk once it gets warmer. 

If you haven't yet?  ...I's start providing some water  ...A deep,  once a week soak,  ...Maybe once every two weeks if your soil  ...5 -8" below   the soil surface..    stays moist for long periods, and / or the weather is cool / chilly..

Use a garden trowel to check,  not a water meter  ..they don't work.